The increased stress was attributed to too many government initiatives plus "increased paperwork, pressure to improve, sheer volume of work and parental pressure".

Heads' concerns about the state of their school buildings were the highest recorded, while worries about staffing and inspections also rose.

But fewer this year flagged up concerns with special education needs and aspects of the curriculum and assessment.

Working with children was the most rewarding aspect of the job for a third of the head teachers, with 30% specifying children's achievement and 21% their development.

Reforms

A Department for Education and Skills spokesperson said vacancy rates for head teacher and deputy head teacher posts were the lowest they had been since 1997.

"Our New Relationship for Schools proposals will cut bureaucracy and red-tape in schools and reduce the number of initiatives so that head teachers can concentrate on the real priorities for school improvement.

"Ofsted's new inspection proposals will also create a new, more professional relationship with schools.

"Our reforms to the teaching workforce are all about freeing teachers and head teachers to do what they do best - teach and lead - giving pupils more individual support in the classroom."

Funding priorities

But the general secretary of the National Association of Head Teachers, David Hart, said the survey "sends a powerful message that primary schools remain under-funded and that primary heads are clearly short of the support they need if they are going to deliver the challenging standards agenda".

As part of the survey, the head teachers were asked how they would spend a hypothetical 5% increase in their budget.

For the tenth year running, extra classroom and welfare assistants and teaching staff remained the top priorities.

Forty-two per cent indicated that administrative and secretarial staff would be prioritised for increased funding; the highest figure there has been.

"This increase may be indicative of the National Workload Agreement introduced at the beginning of 2003, which aimed to relieve pressures on teachers by giving them more time and support to develop teaching and learning, and which will in turn, impact on the role of support staff within schools," NFER observed.

There was less concern about recruiting and retaining teachers.

This probably reflects a rise in the numbers entering the profession and a fall in the number of primary-age children - with signs that many newly-qualified teachers are struggling to find jobs for this autumn.